NASA astronomers using the Hubble telescope have discovered some of 
the smallest, youngest, and most distant galaxies ever observed.
The by-cosmic-standards tiny stellar bodies are so far away, with their light taking so long to reach Earth, that researchers estimate they are essentially seeing back in time to less than a billion years after the big bang. (Astronomers currently pin the post-big-bang universe's age at about 13.7 billion years).
The generally accepted view of galaxies is that they build themselves over time, as smaller individuals coalesce into larger groups. These little bodies appear to predate that process, leading researchers to dub them "Lego block galaxies."
Still, scientists were surprised at how low their apparent mass was – 100 to 1000 times smaller than the Milky Way -- and called on colleagues at the Spitzer Space Telescope observatory to confirm their estimates.
The youthful galaxies offer an unusual look at the formation of stars in the early universe, researchers said. A first generation of sapphire-blue stars glows at their heart, with the absence of red light showing that they are still primarily fusing the simple byproducts of the Big Bang, primarily hydrogen and helium, into heavier elements.
NASA Space Telescopes Find 'Lego-Block' Galaxies in Early Universe [JPL]
(Photo credit: NASA/StScI/ESA)
